Digital image analysis has been applied to several topics in myocardial and valvular research. This project has been renamed from last year to reflect a somewhat broader scope. -Morphometric analysis of myocardial hypertrophy. Software has been developed to enable interactive analysis of samples of hypertrophied myocardium from humans and from experimental animals. These packages allow determination of cell diameter, meter, nuclei densities, capillary densities, and percent interstitium. -Bioprosthetic heart valve studies. To investigate the cause of stenosis of bio-prosthetic valves, diseased valves are removed from experimental animals and imaged radiographically, and after sectioning, by photography. Analysis can quantify sites of calcification, and the amounts of fibrous sheath and normal tissue. -Regional myocardial blood flow. Quantitative data from experimental animals are displayed as a map of the heart, with increases in blood flow indicated by variations in intensity or color. Comparison of epicardial-endocardial flows and control vs. test data will be studied.